Method and User Equipment for Jamming Detection and Signalling in a Mobile Telecommunications Network

1. Method for jamming detection in a mobile telecommunications network comprising the steps of, at a user equipment registered with the mobile telecommunications network: a) measuring a signal power level in at least one of a plurality of communication channels between the user equipment and a base station within a band of operation of the mobile telecommunications network; b) checking whether the signal power level in said at least one communication channel is greater than a threshold MNPL and, if so, attempting to decode a Base Station Identity Code BSIC broadcast by the base station in said communication channel; c) repeating steps a) and b) for a certain number DCMN of channels; d) signalling a jammed condition report JDR message to the base station if said BSIC cannot be decoded for said number DCMN of channels.

2. The method of claim 1 , wherein the signalling step comprises including said JDR message in a Random Access Channel RACH or in a Packet Random Access Channel PRACH.

3. The method of claim 2 , wherein the signalling step comprises including said JDR message in a reserved Information Field of the “Channel Request” message of said RACH or PRACH.

4. The method of claim 1 , wherein the JDR message comprises information identifying the user equipment.

5. The method of claim 4 , wherein said information identifying the user equipment is a Temporary International Mobile Subscriber Identity TMSI code.

6. The method of claim 4 , wherein the signalling step comprises the steps of: transmitting an ordered sequence of JDR messages in respective ones of said RACH/PRACH messages, each JDR message including a predetermined portion of said information identifying said user equipment.

7. The method of claim 6 , further including the step of repeating said ordered sequence of JDR messages for a predetermined number M of times.

8. The method of claim 6 , wherein the JDR messages are sent at predetermined frame numbers.

9. The method of claim 8 , wherein the predetermined frame numbers are chosen among a group of N different sequences of numbers indicating the RACHIPRACH position, each of said sequences of numbers being as long as the bit size of said identifying information divided by the number of bits that can be assigned for identifying said user equipment in said reserved RACHIPRACH information field.

10. The method of claim 9 , wherein said repeating is performed each time on a randomly chosen one of said N sequences of frame numbers among said group.

11. The method of claim 9 , wherein said MNPL, DCMN, M and N are broadcast by the base station.

12. The method of claim 1 , further comprising the steps of: e) receiving a verification request from the network; f) responding to said verification request if the BSIC has been decoded in at least one of said channels.

13. The method of claim 1 , further comprising the steps of, at the Service Provider: receiving said JDR message; verifying the jammed condition according to said JDR message; activating a countermeasure for intervening at the location of the jalnmer causing the jammed condition.

14. User equipment for detecting and signalling a jammed condition to a service provider in a mobile telecommunications network, comprising: means for measuring a signal power level in at least one of a plurality of communication channels between the user equipment and a base station within a band of operation of the mobile telecommunications network; means for checking whether the signal power level in said at least one communication channel is greater than a threshold MNPL; means for decoding a Base Station Identity Code BSIC broadcast by the base station in said communication channel; means for signalling a jammed condition report JDR message to the base station in response to a failure in said decoding for a certain number DCMN of channels in which the signal power level is greater than the MNPL.

15. The user equipment of claim 14 , wherein the means for signalling is programmed so as to include said JDR message in a Random Access Channel RACH or in a Packet Random Access Channel PRACFJ.

16. The user equipment of claim 15 , wherein said JDR message is included in a reserved Information Field of the “Channel Request” message of said RACH or PRACH.

17. The user equipment of claim 14 , wherein the JDR message comprises information identifying the user equipment.

18. The user equipment of claim 17 , wherein the means for signalling are programmed so as to transmit an ordered sequence of JDR messages in respective ones of said RACH/PRACH messages, each JDR message including a predetermined portion of said information identifying said user equipment.

19. The user equipment of claim 18 , wherein said information identifying the user equipment is a Temporary International Mobile Subscriber Identity TMSI code.

20. The user equipment of claim 18 , wherein the means for signalling is programmed so as to repeat said ordered sequence of JDR messages for a predetermined number M of times.

21. The user equipment of claim 20 , wherein the JDR messages are sent at predetermined frame numbers.

22. The user equipment of claim 21 , wherein the predetermined frame numbers are chosen among a group of N different sequences of numbers indicating the RACH position, each of said sequences of numbers being as long as the bit size of said information identifying the user equipment divided by the number of bits that can be assigned for identifying said user equipment in said reserved RACH/PRACH information field.

23. The user equipment of claim 22 , wherein said repeating is performed on a randomly chosen one of said sequences of frame numbers among said group.

24. The user equipment of claim 22 , wherein said MNPL, DCMN, M and N are broadcast by the base station.

25. The user equipment of claim 14 , further comprising means for receiving a verification request from the network, said means for receiving the verification request being set so as to respond to said verification request if the BSIC has been decoded in at least one of said channels.

26. The invention according to claim 14 , wherein said JDR message further comprises location information data.